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Rock glaciers on South Shetland Islands, Antarctic Peninsula, Version 1

In the South Shetland Islands the investigators found eight active rock glaciers, no relict or fossil examples, and seven protalus ramparts. The rock glaciers are located on peninsulas and capes of the two main islands of the archipelago: King George and Livingston. The South Shetland Islands have a cold oceanic climate, characteristic of the maritime Antarctica, with frequent summer rains and moderate thermal amplitude, and a cold and humid morphoclimatic system, of crionival character. These climatic parameters facilitate the operation of periglacial processes, and the presence of a usually saturated active layer in summer. In the South Shetland Islands the presence of rock glaciers have been identified on Livingston Island (Martinez de Pison et al., 1991; Lopez-Martinez et al., 1992a, 1992b), on Admiralty Bay, in King George Island (Birkenmajer, 1981; Barsch et al., 1985) and in Fildes Peninsula (Barsch et al. 1985; Barsch, 1996; Cheng et al., 1996). Four further active rock glaciers have been identified during the present study in King George and Livingston Island (Serrano and Lopez-Martinez, in prep.). The rock glaciers are located in marginal zones, between 300 m asl and sea level, which has been recently deglaciated, and principally under 70 m asl, near 100 m under the Median Equilibrium Line Altitude (MELA). There are indications of a recent diminution of activity, with blurred fronts, mass movements in fronts and sides, lichen colonization and glaciokarstic processes. All of these indicate an inherited dynamic of past conditions in lower altitudes. References to rock glaciers are scarce in Antarctica, limited to a few examples in the Transantarctic Mountains, Victoria Land, South Georgia, James Ross Island, and South Shetland Islands. The spatial pattern of rock glaciers indicates that they are more represented in the periphery of Antarctica than in the interior of the continent, and are particularly numerous in the Antarctic Peninsula region. These data are presented on the CAPS Version 1.0 CD-ROM, June 1998.

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